Its not, because the speech does not include "too / also or again situation"

We never say "yazda". We say "bu yaz" or "yazın". You should study more :=D

That´s tricky (i.e. no yazda is tricky but to study more is not tricky). But I´ve seen Nisanda.?

No, I mean as in  "in the summer" 

If I had meant too/also, then it would have been written as a seperate word: "bu yaz da".

You can say günde, haftada, yılda, baharda but not yazda?

And if you check back, you will see that I did say yazın. You should pay more attention. =))

Lol. Yeah you wrote yazın but you also wrote bu. If you read my post carefully you will see that only bu yaz is acceptable, at least for me. But as a friend I can ignore your mistake if you want

So, if you meant "in the summer", you should say "bu yaz" as gokuyum said.

I know. Because he just told me.

You guys. Really.

Still, none of you smart people has explained why I can´t use ´-da´ with ´bu yaz´. Like I asked. If you had paid attention.

Other than ´you just don´t´. I mean, that´s not a grammatical rule is it?

I think you correct JNQ Couse as you meantionet here before that Turkish language is really hard to know well due to its own Speciall :rules  forexampl Yaz and Yaz seems that same Word but This kinda words meaning only Within Sentences depends your how to Use :  Bu yaz Turkiyeye gideceğim or Bu yaz Kitabımı Yazacağım is an Verb rather than Name like Bu Yaz This Summer or Another verb is Yaza Yaza Bitiremedim kitabı   İ didn`t End up my Book Although I wrote too much 

Riiiiiiight.

If it makes you happy, you can say "yazda"  to mean "in the summer"  and no problem we Turks understand you easily. Dont worry about it. So, i wont pay my attention more.